EddyGraph: The Tracking of Mesoscale Eddy Splitting and Merging Events in the Northwest Pacific Ocean

This paper proposes an algorithm named EddyGraph for tracking mesoscale eddy splitting and merging events. Twenty-seven years (January 1993–December 2019) of sea level anomaly (SLA) data are analyzed in the Northwest Pacific Ocean (105°E–165°W, 0°N–60°N). First, we propose a multilevel eddy identification method based on SLA to obtain an eddytree data set, representing a spatial topological tree structure of closed SLA contours with mononuclear eddies, multicore eddies and eddy seeds as the leaf nodes and eddygroups (reflecting the spatial topological relationship among eddies) as the intermediate nodes. The EddyGraph tracking algorithm is applied to the eddytree data set, which results in eddy-directed acyclic graphs (Eddy-DAGs). Only eddies contained within a common eddygroup are tracked as sources in merging events or sinks in splitting events. Furthermore, we extract typical splitting and merging events and composite the sea surface temperature anomalies (SSTAs) inside the eddygroups and eddies during these events. The results confirm that merging eddies in the same eddygroup degenerate into a single eddy and that a splitting eddy evolves into eddies within the same parent eddygroup. Moreover, we match a merging event of cyclonic eddies with in situ data of both drifters and loopers in Lagrangian trajectories. Finally, we present EddyGraph, a data set of mesoscale eddy tracking in the Northwest Pacific Ocean (105°E–165°W, 0°N–60°N).

Genetic variation and structure of complete chloroplast genome in alien monoecious and dioecious Amaranthus weeds

Amaranthus is a complex taxon with economic importance as well as harmful weeds. We studied the genetic variation and structure of the chloroplast genomes of 22 samples from 17 species of three subgenera. It was found that the length of the chloroplast genome of Amaranthus varied from 149,949 bp of A. polygonoides to 150,757 bp of A. albus. The frequencies of SNPs and InDels in chloroplast genomes were 1.79 % and 2.86 %, and the variation mainly occurred in the non-coding regions. The longest InDel was 387 bp, which occurred on ycf2, followed by 384 bp InDel on psbM-trnD. Two InDels in ndhE-I on the SSC make the three subgenera clearly distinguished. In LSC, SSC and IRs regions, there were four 30 bp forward and reverse repeats, and the repeats in SSC and LSC were in nearly opposite positions in circular genome structure, and almost divided the circular genome into symmetrical structures. In the topological tree constructed by chloroplast genome, species in subgen. Amaranthus and subgen. Acnida form monophyletic branches separately and cluster together. A. albus, A. blitoides and A. polygonoides were separated from subgen. Albersia, and the rest of subgen. Albersia were clustered into a monophyletic branch. The rpoC2, ycf1, ndhF-rpl32 were good at distinguishing most amaranths. The trnk-UUU-atpF, trnT-UGU-atpB, psbE-clpP, rpl14-rps19, and ndhF-D can distinguish several similar species. In general, the chloroplast genome is of certain value for the identification of the similar species of Amaranthus, which provides more evidence for clarifying the phylogenetic relationships within the genus.

Examples of codification of the dynamics of arational function into a topological tree

in 1736 L. Euler gave solution to the famous Seven Bridges ofKönigsberg problem, considerin a graph consisting of nodesrepresenting thelandmasses and arcs representing the bridges. This problemis a referent ofhow to codify the information given of a problem into a simpler and richerstructure. In the case of the Dynamics of rational functions, Shishikura in[5] explores this idea in the context of rational functions,and he stated aconnection between a certain kind of topological tree with ap-cycle of Hermanrings associated to a rational function. In this work we develop some examplesof realizable configurations for rational functions, two ofthem sketched in [5],and an example of a non realizable configuration which we modify in orderto be realizable.

Towards Reconstructing 3D Buildings from ALS Data Based on Gestalt Laws

3D building models are an essential data infrastructure for various applications in a smart city system, since they facilitate spatial queries, spatial analysis, and interactive visualization. Due to the highly complex nature of building structures, automatically reconstructing 3D buildings from point clouds remains a challenging task. In this paper, a Roof Attribute Graph (RAG) method is proposed to describe the decomposition and topological relations within a complicated roof structure. Furthermore, top-down decomposition and bottom-up refinement processes are proposed to reconstruct roof parts according to the Gestalt laws, generating a complete structural model with a hierarchical topological tree. Two LiDAR datasets from Guangdong (China) and Vaihingen (Germany) with different point densities were used in our study. Experimental results, including the assessment on Vaihingen standardized by the International Society for Photogrammetry and Remote Sensing (ISPRS), show that the proposed method can be used to model 3D building roofs with high quality results as demonstrated by the completeness and correctness metrics presented in this paper.